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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 311-323页

作者： Yanqin li Daohui xiang Guofu GAO Feng JIAO Bo ZHAO School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454000China

Ultrasonic vibration grinding differs from traditional grinding in terms of its material removal *** randomness of grain-workpiece interaction in ultrasonic vibration grinding can produce variable chips and impact the surface roughness of ***,previous studies used iterative method to calculate the unformed chip thickness(UCT),which has low computational *** this study,a symbolic difference method is proposed to calculate the *** UCT distributions are obtained to describe the stochastic interaction characteristics of ultrasonic grinding ***,the UCT distribution characteristics under different machining parameters are ***,a surface roughness prediction model is established based on the UCT ***,the correctness of the model is verified by *** study provides a quick and accurate method for predicting surface roughness in longitudinal ultrasonic vibration grinding.

关键词： Ultrasonic vibration grinding Undeformed chip thickness(UCT) Distribution characteristics Surface roughness

A Weakly-Supervised Crowd Density Estimation Method Based on Two-Stage linear Feature Calibration

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 965-981页

作者： Yong-Chao li Rui-Sheng Jia Ying-xiang Hu Hong-Mei Sun the College of Computer Science and Engineering Shandong University of Science and TechnologyQingdao 266590 the Faculty of Information Science and Engineering Ocean University of ChinaQingdao 266000China the College of Computer Science and Engineering Shandong University of Science and TechnologyQingdao 266590China the College of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210000China

In a crowd density estimation dataset,the annotation of crowd locations is an extremely laborious task,and they are not taken into the evaluation *** this paper,we aim to reduce the annotation cost of crowd datasets,and propose a crowd density estimation method based on weakly-supervised learning,in the absence of crowd position supervision information,which directly reduces the number of crowds by using the number of pedestrians in the image as the supervised *** this purpose,we design a new training method,which exploits the correlation between global and local image features by incremental learning to train the ***,we design a parent-child network(PC-Net)focusing on the global and local image respectively,and propose a linear feature calibration structure to train the PC-Net simultaneously,and the child network learns feature transfer factors and feature bias weights,and uses the transfer factors and bias weights to linearly feature calibrate the features extracted from the Parent network,to improve the convergence of the network by using local features hidden in the crowd *** addition,we use the pyramid vision transformer as the backbone of the PC-Net to extract crowd features at different levels,and design a global-local feature loss function(L2).We combine it with a crowd counting loss(LC)to enhance the sensitivity of the network to crowd features during the training process,which effectively improves the accuracy of crowd density *** experimental results show that the PC-Net significantly reduces the gap between fullysupervised and weakly-supervised crowd density estimation,and outperforms the comparison methods on five datasets of Shanghai Tech Part A,ShanghaiTech Part B,UCF_CC_50,UCF_QNRF and JHU-CROWD++.

关键词： Crowd density estimation linear feature calibration vision transformer weakly-supervision learning

Enhanced electric-field induced strain in Eu^(3+) doped 0.67BiFeO_(3)-0.33BaTiO_(3) lead-free piezoelectric ceramics

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Journal of Rare Earths 2024年第9期42卷 1747-1754,I0004页

作者： Wei li Tongxiang liang xiang He Vyunov Oleg Dongfang Pang Shan Wu College of Rare Earths Jiangxi University of Science and TechnologyGanzhou341000China Key Laboratory of High Performance Ceramics and Ultrastructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai201800China

Lead-free ferroelectric ceramics,0.67Bi_(1-x)Eu_(x)FeO_(3)-0.33BaTiO_(3)(BF-BT-xEu,x=0-0.02),were prepared via a solid-state reaction,The effect of Eu^(3+) doping on the microstructure,dielectric properties,ferroelectric properties,and electric-field-induced strain was *** X-ray diffraction(XRD) results indicate the presence of a mixed phase of tetragonal and rhombohedral at the morphotropic phase boundary(MPB).Doping with an appropriate amount of Eu^(3+) reduces the Fe^(3+) content and decreases the leakage current in the binary system.A converse piezoelectric coefficient(d_(33)*) of 392 pm/V is obtained at BF-BT-0.003Eu under an electric field of 60 kV/cm at room temperature,which has a Curie temperature(T_C) of 414℃,The unipolar strain and d_(33)* of BF-BT-0.003Eu ceramics increase to 0.438%and 730 pm/V at 125℃ The field-induced strain response of the BF-BT-0.003Eu ceramics is greater than that of 0.67BF-0.33BT,mainly due to its optimal grain size,reduction of leakage current,and coexistence of ferroelectric-relaxation phases,BF-BT-0.003Eu ceramic is a lead-free candidate for high-temperature actuator applications.

关键词： Ferroelectric Field-induced strain Ceramics Lead-free Rare earths

Numerical simulation of aircraft arresting process with an efficient full-scale rigid-flexible coupling dynamic model

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Chinese Journal of Aeronautics 2024年第5期37卷 586-602页

作者： Haoyuan SHAO Daochun li Zi KAN Lanxi BI Zhuoer YAO Jinwu xiang School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Tianmushan Laboratory Hangzhou 310023China

The arresting process of carrier-based aircraft is widely recognized as a challenging task,characterized by the highest accident rate among all carrier-based aircraft *** simulation plays a crucial role in assessing the intricate responses of the arresting process,favoring the design of carrier-based *** efficient and accurate rigid-flexible coupling model for analyzing the dynamic response of the arresting process is *** combining the dynamic characteristics of airframe,landing gear,arresting hook and arresting gear system,the rigid-flexible coupling dynamic model is established to reflect the relative motion of the coupling parts and arresting *** dynamic model is verified through simulations of landing gear landing drops and by comparing the arresting simulation results with corresponding data in the US military ***,simulations of the arresting process under different off-center distance and aircraft yaw angle are conducted to obtain the dynamic response of the aircraft during the arresting *** result indicates that the rigid-flexible coupling dynamic model proposed is effective for analyzing the arresting dynamics response of carrier-based *** axial force of the arresting cable on both sides of the hook engagement point,pitch and yaw angle of aircraft are inconsistent under yaw and off-center *** analysis method and obtained results provide valuable references for assessing the dynamic responses of carrier-based aircraft during arresting process and offer valuable in-sights in the design of carrier-based aircraft.

关键词： Carrier-based aircraft Deck landing Rigid-flexible coupling dynamic model Finite element method Dynamic analysis

Propagation form of internal cracks induced by continuous casting soft reduction and control strategy for internal quality

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Journal of Iron and Steel Research International 2024年第3期31卷 622-633页

作者： Pu Wang liang Chen Qun-wei Tang Wei-tao li Shao-xiang li Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Weifang Special Steel Group Co..Ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were *** results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross *** cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or *** control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of *** this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： Continuous casting Soft reduction Crack propagation Internal quality Control strategy

Energy Absorption by 3D-Printed Mesh Structures with a Negative Poisson’s Ratio

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 205-212页

作者： Wenyu li Weiming Yang Mingze li xiang Zhang Ping Zhang Yucheng Zhao Peijian Chen Haishun liu School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou221116China School of Materials Sciences and Physics China University of Mining and TechnologyXuzhou221116China

A negative Poisson's ratio(NPR)structure represents optimal impact-resistance with applications in various fields,including the crash box in vehicles,which absorbs impact kinetic *** crash box is designed to deform in response to impact,increasing local structural density,which enhances impact resistance *** studies have only focused on the NPR effect in the plane dimension at low-speed *** studies have considered high-speed impact loads on three-dimensional NPR *** have developed two types of AlSi10Mg alloy energy-absorbing structures with NPR using three-dimensional printing technology,and have compared our systems with a conventional hexagonal mesh *** testing involved split-Hopkinson pressure bar measurements,which showed good agreement with dynamic numerical *** subjected to an impact load,the NPR structure exhibited better impact resistance and energy absorption compared with the positive Poisson's ratio *** proposed dual-layer hexagonal structure ensures an NPR effect while exhibiting higher strength and improved stability relative to the conventional concave hexagon structure.

关键词： Negative Poisson’s ratio Energy absorption 3D printing Split-Hopkinson pressure bar Numerical simulation

Renewable biosynthesis of isoprene from wastewater through a synthetic biology approach:the role of individual organic compounds

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 13-24页

作者： Min Yang xianghui li Weixiang Chao xiang Gao Huan Wang Lu Lu State Key Laboratory of Urban Water Resource and Environment School of Civil and Environmental EngineeringHarbin Institute of TechnologyShenzhen 518055China Center for Materials Synthetic Biology CAS Key Laboratory of Quantitative Engineering Biology of CASShenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academic of ScienceShenzhen 518000China Institute of Urban Ecology and Environmental Technology School of Materials and Environmental EngineeringShenzhen Polytechnic UniversityShenzhen 518055China

The biosynthesis of isoprene offers a more sustainable alternative to fossil fuel-based approaches,yet its success has been largely limited to pure organic compounds and the cost remains a *** study proposes a waste-to-wealth strategy for isoprene biosynthesis utilizing genetically engineered *** bacteria to convert organic waste from real food *** impact of organic compounds present in wastewater on *** growth and isoprene production was systematically *** results demonstrated that with filtration pretreatment of wastewater,isoprene yield,and production achieved 115 mg/g COD and 7.1 mg/(L·h),***,even without pretreatment,isoprene yield only decreased by~24%,indicating promising ***,maltose,glycerol,and lactate are effective substrates for isoprene biosynthesis,whereas starch,protein,and acetate do not support *** *** optimum C/N ratio for isoprene production was found to be 8:***,augmenting essential nutrients in wastewater elevated the isoprene yield increased to 159 mg/g *** wastewater biosynthesis significantly reduced the cost(44%–53%decrease,p-value<0.01)and CO_(2)emission(46%–55%decrease,p-value<0.01)compared with both sugar fermentation and fossil fuel–based *** study introduced a more sustainable and economically viable approach to isoprene synthesis,offering an avenue for resource recovery from wastewater.

关键词： Wastewater Resource recovery Genetic engineering Biosynthesis Isoprene

pH Induced Self-assembly of AIE Fluorescent Probe for Tumor Imaging

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Chinese Journal of Polymer Science 2024年第1期42卷 7-13,I0005页

作者： Jing-Yuan xiang Wen-Long Zhang He-Ting li Ya-Ning He Department of Chemical Engineering Key Laboratory of Advanced Materials(MOE)Tsinghua UniversityBejing 100084China

This work reported an AIE fluorescent probe for tumor imaging based on the p H induced self-assembly strategy. The fluorescent probe was composed of an acid-responsive soluble copolymer PEG-b-PAMA-DMMA with a maleic acid amide group and an anionic soluble aggregation-induced emission fluorogen(AIEgen) TPE-2SO_(3)^(-). The polymer could be transformed into a protonated amine-containing polymer after the hydrolysis of maleic acid amide in acidic tumor microenvironment, which would be further self-assembled with TPE-2SO_(3)^(-)to form aggregated nanoparticles. The transition of TPE-2SO_(3)^(-)from dispersed state to aggregated state led to an obvious increase in fluorescence intensity due to its AIE characteristics.

关键词： p H-responsive Self-assembly Fluorescent probe AIE Tumor imaging

Concept, configuration, and application of on-board nanogrids for use in electric vehicles

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Science China(Technological Sciences) 2024年第7期67卷 2053-2073页

作者： ZHAO Bing li Yong WU fang WAN JiangHu CAI JiuQing YANG HaiTao liU fang College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Wuhan Second Ship Design and Research Institute Wuhan 430000China School of Automation Central South UniversityChangsha 410083China

Against the backdrop of increasingly serious climate change, researchers are attempting to extend macroscale carbon reduction research to smaller scales. With the rapid development and widespread application of electric vehicles(EVs), an effective approach for carbon reduction based on EVs has the potential to be developed. To coordinate and manage the EV platform in diverse application scenarios, the concept of an on-board nanogrid(OBNG), in which a nanogrid is combined with the EV, is proposed and defined, and the characteristics summarized. A configuration that includes a physical layer with the on-board hardware system;an information layer for logical control, energy management, and communication coordination;and an application layer that can cope with different working environments is proposed. A detailed introduction to the basic architecture and management mode of each layer is provided along with information concerning the relevant technologies for coordinated operation. New ideas and approaches to improve the existing performance are proposed, and finally, combined with a background of smart and low-carbon cities, major application scenarios are envisioned.

关键词： electric vehicle nanogrid energy management hybrid energy storage power electronics converter

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Pyrolysis of Copper Phthalocyanine as Non-noble Metal Electrocatalysts for Oxygen Reduction Reaction

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1087-1092页

作者： ZHANG lijuan LU Jinhua WANG Yan li xiang School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China State Key Laboratory of Solidification Processing Carbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an710072China

We investigated the relationship between oxygen reduction reaction(ORR)activity and the pyrolysis temperature(650-850℃)of CuPc in alkaline *** highly active sites were formed through the decomposition of CuPc or Cu-N4 structure after releasing ***-Nx incorporated with carbon were the main active *** XPS measurement results show that,at lower temperature,the contents of pyridinic-N and pyrrolic-N account for the most of the total *** the temperature is higher than 750℃,the content of graphitic N(26.11%)increases and pyridinic-N(58.81%)becomes the dominant *** the temperature is higher than 850℃,the content of graphitic N increases remarkably and becomes the dominant ***,the specific surface areas decrease with increased pyrolysis *** from the synergistic effect,the pyrolysis temperature at 750℃of CuPc displays superior electrocatalytic *** obtained results reveal that the fabricated non-noble metal catalysts can be used as low-cost,efficient catalyst for water splitting ORR in metal-air batteries and fuel cells.

关键词： copper phthalocyanine pyrolysis electrocatalytic oxygen reduction reaction